William C. Miller

Older Adults, Chronic Disease and Leisure-Time Physical Activity

Background: Participating in regular physical activity is an important part of healthy aging. There is an increased risk for inactivity associated with aging and the risk becomes greater for adults who have a chronic disease. However, there is limited information on current physical activity levels for older adults and even less for those with chronic diseases. Objective: Our primary objective was to determine the proportion of older adults who achieved a recommended amount of weekly physical activity (≥1,000 kcal/week). The secondary objectives were to identify variables associated with meeting guideline leisure-time physical activity (LTPA), and to describe the type of physical activities that respondents reported across different chronic diseases. Methods: In this study we used the Canadian Community Health Survey Cycle 1.1 (2000/2001) to report LTPA for adults aged 65 years and older. This was a population-based self-report telephone survey. We used univariate logistic regression to provide odds ratios to determine differences in activity and the likelihood of meeting guideline recommendations. Results: For adults over 65 years of age with no chronic diseases, 30% reported meeting guideline LTPA, while only 23% met the recommendations if they had one or more chronic diseases. Factors associated with achieving the guideline amount of physical activity included a higher level of education, higherincome and moderate alcohol consumption. Likelihood for not achieving the recommended level of LTPA included low BMI, pain and the presence of mobility and dexterity problems. Walking, gardening and home exercises were the three most frequent types of reported physical activities. Conclusion: This study provides the most recent evidence to suggest that older Canadians are not active enough and this is accentuated if a chronic disease is present. It is important to develop community-based programs to facilitate LTPA, in particular for older people with a chronic disease.

Measurement properties of the Activities-specific Balance Confidence Scale among individuals with stroke

Purpose: To examine the reliability and validity of the Activities-specific Balance Confidence (ABC) Scale among individuals with stroke. Method: Descriptive measurement study using a 4-week test – retest design. Data were collected at a tertiary rehabilitation centre from a community-dwelling sample of ambulatory older adults who sustained one stroke at least 1 year prior to the study. During the first measurement session, the total sample (n = 77) completed the ABC as well as the Berg Balance Scale (BBS) and gait speed. The reliability sample (n = 24), a subset of the larger data set, completed the ABC again 4 weeks later. Results: Internal consistency of the ABC was 0.94 and test – retest reliability was ICC = 0.85 (95% CI, 0.68, 0.93). A moderate significant positive, linear correlation with both the BBS (ρ = 0.36, P < 0.001) and gait speed (ρ = 0.48, P < 0.001) was observed. A factor analysis using principal component analysis indicated that the ABC measures two components of balance self-efficacy (component 1 = perceived low-risk activities; component 2 = perceived high-risk activities). Conclusions: The ABC has acceptable measurement properties as demonstrated in this sample of individuals with stroke. This study provides further support for the use of the scale.

Psychometric properties of the Activities-specific Balance Confidence scale among individuals with a lower-limb amputation

OBJECTIVE To evaluate the internal consistency, test-retest reliability, and construct validity of the Activities-specific Balance Confidence (ABC) Scale among people who have a lower-limb amputation. DESIGN Retest design. SETTING A university-affiliated outpatient amputee clinic in Ontario. PARTICIPANTS Two samples of individuals who have unilateral transtibial and transfemoral amputation. Sample 1 (n=54) was a consecutive and sample 2 (n=329) a convenience sample of all members of the clinic population. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Repeated application of the ABC Scale, a 16-item questionnaire that assesses confidence in performing various mobility-related tasks. Correlation to test hypothesized relationships between the ABC Scale and the 2-minute walk (2MWT) and the timed up-and-go (TUG) tests; and assessment of the ability of the ABC Scale to discriminate among groups based on amputation cause, amputation level, mobility device use, automatic stepping ability, wearing time, stair climbing ability, and walking distance. RESULTS Test-retest reliability (intraclass correlation coefficient) of the ABC Scale was .91 (95% confidence interval [CI], .84-.95) with individual item test-retest coefficients ranging from .53 to .87. Internal consistency, measured by Cronbach alpha, was .95. Hypothesized associations with the 2MWT and TUG test were observed with correlations of .72 (95% CI, .56-.84) and -.70 (95% CI, -.82 to -.53), respectively. The ABC Scale discriminated between all groups except those based on amputation level. CONCLUSIONS Balance confidence, as measured by the ABC Scale, is a construct that provides unique information potentially useful to clinicians who provide amputee rehabilitation. The ABC Scale is reliable, with strong support for validity. Study of the scales responsiveness is recommended.

A prospective study examining balance confidence among individuals with lower limb amputation

Purpose: In this study we assessed whether balance confidence scores changed over a 2-year follow up period, and identified predictors of balance confidence and predictors of change in balance confidence among lower limb amputees. Method: A prospective follow-up survey of 245 community living adults with unilateral below and above knee lower limb amputation who used their prosthetic limb daily was conducted. Balance confidence, assessed using the 16-item Activity-specific Balance Confidence (ABC) Scale, socio-demographic, health and amputation related variables were collected at baseline and 2 years later. Results: ABC scores were similar at baseline (mean = 67.6; SD = 25.7) and follow up (mean = 68.0; SD = 25.8). Lower balance confidence scores at follow up were predicted by older age, being female, use of a mobility device, poor perceived health, increased symptoms of depression, having to concentrate while walking, and fear of falling (all p < 0.05). Predictors of change in balance confidence included gender and perceived health (all p < 0.05). Conclusion: Balance confidence appears to be a persistent problem in the amputee population. Health professionals are encouraged to consider balance confidence as a potentially important variable that may influence function in this clinically unique group of individuals. The identified predictor variables may be useful to clinicians in targeting individuals who require attention to improve balance confidence.

Measuring energy expenditure using heart rate to assess the effects of wheelchair tyre pressure

Objective: To investigate the effects of wheelchair tyre pressure on mechanics and energy and explore the use of heart rate as a measurement of energy expenditure. Design: A single factor repeated measures design was used. Four tyre pressures (100, 75, 50, 25 psi) represented a change of workload. Each subject wheeled at a constant self-selected wheeling velocity for 8 min. A total of four trials were completed with a 10-min rest between trials. Oxygen consumption, heart rate and distance travelled were collected during each trial. Subjects: Three women and 11 men with spinal cord injury. The mean age for the whole group was 34.5 years. The range of lesion level was T4-L1. Results: There was a significant increase is energy expenditure when tyres were deflated to 50 psi from 100 psi. The mean correlation between heart rate and oxygen consumption was 0.74 for all subjects. For the subjects with lesions above T6 and T6 and below the correlations were 0.55 and 0.82, respectively. Conclusions: Tyre pressures below 50% inflation add an additional 25% increase in energy expenditure during wheeling. This could be detected using oxygen consumption or heart rate, as heart rate was shown to have a good correlation with oxygen consumption in the spinal cord injured with lesions below T5. Heart rate does have its limitations and it should only be used to measure within-subject differences.

Overarching principles and salient findings for inclusion in guidelines for power mobility use within residential care facilities.

Although power mobility has many potential benefits for users, power mobility incidents and accidents are a serious concern. To date, little research has explored power mobility safety, and no gold standard exists to determine whether the user is a safe driver. As a possible alternative to a facility unilaterally imposing regulations on power mobility users, we conducted a research project in which power mobility users and other stakeholders used the Delphi method to develop guidelines for power mobility use within a residential facility setting. This article presents the overarching principles for power mobility use and noteworthy items from the safety guidelines that participants developed. These findings highlight the safety issues that are encountered in residential care settings and suggest some strategies to deal with them.

Reliability of the Chinese version of the Activities-specific Balance Confidence Scale

Purpose. To translate the Activities-specific Balance Confidence (ABC) Scale into a Chinese version and assess the reliability between Chinese versions and between Chinese and English versions of this outcome measure. Method. Descriptive study using a 4-week test-retest design. Data were collected from a convenience sample of community living Chinese immigrants. Of the 79 participants, data from 71 subjects were included in the analysis. Two subsamples were formed to assess the reliability between Chinese versions (n = 33) and between Chinese and English versions (n = 38) of the scale. Results. Internal consistency of the ABC-C was 0.98. Test-retest reliability was intraclass correlation coefficient (ICC) = 0.87 (95% CI, 0.76 – 0.93) for the Chinese versions and ICC = 0.88 (95% CI, 0.78 – 0.94) for Chinese and English versions. The total group ICC = 0.90 (95% CI, 0.84 – 0.94). Conclusions. Balance confidence has been identified as an important area for clinical and research inquiry however collecting this information from Chinese speaking individuals has been limited by a lack of language specific measures. The Chinese version of the ABC has demonstrated acceptable measurement properties in this sample and should permit measurement of this unique construct in the Chinese population.

Development and preliminary assessment of the measurement properties of the Seating Identification Tool (SIT)1

Objective: To present and discuss the development and measurement properties of the Seating Identification Tool (SIT), a screening tool designed to identify the need for formal seating and wheelchair intervention among institutionalized elderly. Specifically, investigation of the inter-rater and test–retest reliability, sensitivity, specificity, the positive and negative predictive values of the SIT was conducted. Design: A two-week retest design. Setting: A long-term care facility in London, Ontario, Canada. Subjects: Forty-two randomly selected residents with an average age of 83 years who had a disability and required the use of a wheelchair as their main mode of mobility. Intervention: Two health care assistants from a long-term facility collected data using the SIT. One rater assessed all subjects two weeks later to evaluate test–retest reliability. Diagnostic properties (validity) were determined by having all subjects assessed by a seating therapist. Main measurement: The SIT and formal evaluation by a therapist experienced in seating. Results: The ICC for both test–retest and inter-rater reliability was 0.83. A cut-off score of 2 maximized the sensitivity (100%) and specificity (64% and 57% for raters 1 and 2 respectively) and the area under the receiver operating characteristics curve (0.855 and 0.862 for raters 1 and 2). The positive and negative predictive values ranged from 82 to 100%. Conclusion: The SIT is a quick, easy to use, reliable and valid screening tool that can be used to facilitate clinical referral for formal intervention. Other potential uses include population-based surveys to estimate the need for including seating intervention in strategic planning for the institutionalized elderly.

Health, Personal, and Environmental Predictors of Wheelchair-Use Confidence in Adult Wheelchair Users

Background There are no predictive models of wheelchair-use confidence. Therefore, clinicians and researchers are limited in their ability to screen for and identify wheelchair users who may be more prone to low wheelchair-use confidence and may benefit from clinical intervention. Objective The purpose of this study was to identify health-related, personal, and environmental factors that predict perceived wheelchair-use confidence in community-dwelling adults who use manual wheelchairs. Design A cross-sectional study was conducted. Methods Community-dwelling manual wheelchair users (N=124) were included in the study if they were ≥50 years of age, had ≥6 months of wheelchair use experience, and had no cognitive impairment. The Wheelchair Use Confidence Scale was used to assess wheelchair-use confidence. The sociodemographic information form, Functional Comorbidity Index, Seating Identification Tool, Interpersonal Support and Evaluation List, and Home and Community Environment Instrument captured the independent variables. Blocks of health, personal, and environmental variables were sequentially entered into the regression model. Results Five personal variables (age, standardized beta [β]=−0.18; sex, β=−0.26; daily hours of wheelchair occupancy, β=0.20; wheelchair-use training, β=0.20; and wheelchair-use assistance, β=−0.34) and one environmental variable (need for seating intervention, β=−0.18) were statistically significant predictors, explaining 44% of the confidence variance. Limitations The sample comprised volunteers and, therefore, may underrepresent or overrepresent particular groups within the population. The studys cross-sectional research design does not allow for conclusions to be made regarding causality. Conclusion Older women who use wheelchairs and who require assistance with wheelchair use may have low wheelchair-use confidence. The same is true for individuals who have no formal wheelchair-use training, who are in need of a seating intervention, and who report few hours of daily wheelchair use. These wheelchair users may require clinical attention and benefit from intervention.